/**
 * @file: graph.h 
 * Graph class definition/implementation.
 */
/*
 * Graph library, internal representation of graphs in ShowGraph tool.
 * Copyright (c) 2009, Boris Shurygin
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef GRAPH_H
#define GRAPH_H

/**
 * @class Graph
 * @brief Basic representation of graph
 * @ingroup GraphBase
 *
 * @par 
 * The Graph class represents graph as a whole. As one can expect graph has @ref Node "nodes"
 * and @ref Edge edges which impement the directed graph data structure. For traversing nodes
 * and edges they are linked in two lists. One can traverse these lists using firstNode() and firstEdge()
 * routines with calling Node::nextNode() Edge::nextEdge() in a loop.
 * Example:
 * @code
 //Traversing nodes
 for ( Node *n = firstNode(); isNotNullP( n); n = n->nextNode())
 {
     ...
 }
 //Traversing edges
 for ( Node *e = firstEdge(); isNotNullP( e); e = e->nextEdge())
 {
     ...
 }
 @endcode
 * The same result can be achieved using macros 
 * @code
 
 // Graph *g; Node *n; Edge *e;
 // Traversing nodes
 foreachNode( n, g)
 {
    ...
 }
 
 // Traversing edges
 foreachEdge( e, g)
 {
    ...
 }
 @endcode
 *
 * @par
 * The graph is also owner of memory allocated for its nodes and edges. This is
 * implemented via @ref FixedPool "memory pools" with records of fixed size. Nodes and
 * Edges should be created through newNode() and newEdge() routines. They can be deleted by
 * deleteNode() and deleteEdge() routines. Do not use operators new/delete for graph's 
 * nodes and edges.
 * 
 * @par
 * Graph is also manager of @ref Mark "markers" and @ref Nums "numerations" for nodes and edges.
 * New @ref Marker "marker" can be obtained by newMarker() routine. New @ref Numeration "numeration" is
 * created by newNum().
 * Example:
 * @code
 //Graph *graph; Node *n;
 Marker m = graph.newMarker();
 Numeration num = graph.newNum();
    
 GraphNum i = 0; //unsigned int 32
 //Mark nodes without predecessors
 foreachNode( n, g)
 {
    if ( isNullP( n->firstPred()))
    {
        n->mark( m);
        n->setNumber( num, i++);
    }
 }
 ...

 //Checking markers and numbers
 foreachNode( n, g)
 {
     if ( n->isMarked( m) && n->number( num) > 10)
     {
        ...
     }
 }
 graph->freeMarker( m);
 graph->freeNum( num);

 @endcode
 *
 * @par Deriving classes from Graph
 * To make a graph-like data structure one can use Graph as a base class. Most likely
 * it will be also necessary to implement two more classes to make a useful implementation.
 * These two class should be derived from Node and Edge to represent information  
 * associated with nodes and edges. You can see an example of such inheritance in AGraph,
 * ANode and AEdge classes.
 *
 * @sa Node
 * @sa Edge
 * @sa Mark
 * @sa Nums
 * @sa AGraph
 */
class Graph: public MarkerManager, public NumManager, public QDomDocument
{
public:
    /**
     * Constructor. 
     * Derived classes may be call constructor with 'false' vaule of
     * the parameter to prevent pools creation for base-level nodes and edges.
     * In this case pool should be created by derived class itself.
     */
    Graph( bool create_pools);
    
    /** Destructor */
    virtual ~Graph();

    /** Create new node in graph */
    inline Node * newNode();

    /** Create new node in graph and fills it with info in element */
    inline Node * newNode( QDomElement e);

    /**
     * Create edge between two nodes.
     * We do not support creation of edge with undefined endpoints
     */
    inline Edge * newEdge( Node * pred, Node * succ);
    /**
     * Create edge between two nodes from an XML description
     * We do not support creation of edge with undefined endpoints
     */
	inline Edge * newEdge( Node * pred, Node * succ, QDomElement e);
    
    /** 
     *  Delete node. Substitution for node's operator delete, which shouldn't
     *  be called directly since Node is a pool-residing object
     */
    inline void deleteNode( void *n);

    /** 
     *  Delete node. Substitution for edges's operator delete, which shouldn't
     *  be called directly since Edge is a pool-residing object
     */
    inline void deleteEdge( void *e);
    
    /** Remove node from node list of graph */
    inline void detachNode( Node* node);

    /** Remove edge from edge list of graph */
    inline void detachEdge( Edge * edge);

    /** Return number of nodes in graph */
    inline GraphNum nodeCount() const;

    /** Return number of edges in graph */
    inline GraphNum edgeCount() const;
    
    /** Get first edge */
    inline Edge* firstEdge();

    /** Get first node */
    inline Node* firstNode();
    
    /** Print graph to stdout in DOT format */
    virtual void debugPrint();
 
    /**
     * Save graph as an XML file
     */
    virtual void writeToXML( QString filename);

    /**
     * Build graph from XML description
     */
    virtual void readFromXML( QString filename);

protected:

    /** Node creation routine is to be overloaded by derived class */
	virtual Node * createNode( int _id);
	/** Edge creation routine is to be overloaded by derived class */
    virtual Edge * createEdge( int _id, Node *_pred, Node* _succ);
    
    /** Pools' creation routine */
    virtual void createPools();
    /** Pools' destruction routine */
    virtual void destroyPools();

    /** Get pool of nodes */
    inline Pool *nodePool() const;
    /** Get pool of edges */
    inline Pool *edgePool() const;

    /** Memory pool for nodes */
    Pool *node_pool;
    /** Memory pool for edges */
    Pool *edge_pool;
private:
    /**
     * Implementation of node creation
     */
    inline Node * newNodeImpl( GraphUid id);
    /**
     * Implementation of edge creation
     */
	inline Edge * newEdgeImpl( Node * pred, Node * succ);

    /** Clear unused markers from marked objects */
    void clearMarkersInObjects();

    /** Clear unused numerations from numbered objects */
    void clearNumerationsInObjects();

    /** First node */
    Node* first_node;
    /** Number of nodes */
    GraphNum node_num;
    
    /** 
     *  Id of next node. Incremented each time you create a node,
     *  needed for nodes to have unique id. In DEBUG mode node id is not reused.
     */
    GraphUid node_next_id;

    /* List of edges and its iterator */
    Edge* first_edge;
    GraphNum edge_num;
    
    /** Id of next edge. Incremented each time you create an edge,
     *  needed for edges to have unique id. In DEBUG mode edge id is not reused.
     */
    GraphUid edge_next_id;
};

#endif
